Manhole frame cover



Bm 15? w35., C, M MQORE 1,988,360

MANHOLE FRAME COVER Filed OO'E. 28, 1952 z2 l@ w19@ (15 Patented `lan. 15, 1935 Qapplication?octobeszs,

1932, serial Nei-cacher 7 Thisv invention relates 'generally to'v lstreet .manhole frames and icovers, and particularly nto structuresfof this kindfformedwof pressed vste@ and involving a locking means tofpreventaocidental -or .unauthorized removal of the cover from the opening. A

Thefprimaryv object-of the invention is to vprovide avframe Aand cover-constructed rin'such inaniner1as-to=atially timesinsure a properr seating 4oi? .the-lid or covers in the i frame and-to obv-iate' the .possibility ofrattling. A A further object `of theginventioiris -toprovide yimproved.means for locking .thecover-in posi- .tion'withinlthe frame. l

With these objects in view, .together with @others which jwill 1 appear asthe .description :proneeds;v the linvention consists-in the novel? construction, .combination- `and arrangement of parts, '.all #asf -will lbemore' `fully `disclosed'herein'- vafter', yillustratedbinI 'the' idrawing, andiv particuilarlyepointediout inftheclaima-k- -f Infthe drawing;-

Fig. :1y iis :a4-top :plan rviewe'oftheimproved imanfholeframeand cover constructed :inv-.accordance withv fthe invention, y

Fig. 2 is a transverse sectional*view-:takenfsubstantially upon the line 2-2 of Fig. 1 and disclosing :the locking-means in elevation,

Fig. 3 is a similar View taken upon the line 3-3 of Fig. 1, and

Fig. 4 is an enlarged fragmentary sectional view taken through the frame and cover and disclosing the construction and method of operation of the improved locking means.

It has heretofore been the practice to `construct manhole frames and covers of cast metal, but an objection arises in that irregularities often occur either in the cover seat or in the cover itself causing an improper t of the cover and resulting in an objectionable rattling of the cover when encountered by vehicular traffic. In instances where it is required that the cover be locked within the frame, it has been the practice to apply and lock the cover with a rotary movement of the cover. In removing the cover it has been necessary to release the locking means and then apply retrograde rotary motion to the cover in order to fully disengage the locking means. A serious objection to this method of locking is that after a time t'ar, grease, dirt and other foreign matter become packed in the groove between the cover and frame so tightly as to make it most difficult, if not impossible, for a single operator to give to the cover the rotary movement, however-.slight, necessary Itio-.disenfgagevthe cover lfrom: the frame. Y

It-isfanobject ofv the present#inventiontofprovidea manhole frame 4andfcover of such, 4 char- .acter vandconstruction,as/to obviate theaboveA `l5 lmentioned serious objections, as .well as toyprovide a simplified and -improvedvlocking meanswhichis assembled within the structure in-such Vmanner as to ber proof` against breakage, l.corroi, sion or derangement, which/isat all times .operl0 ableygby those possessed ofA a lknowledge of its Yconstituction and operation, 'which rigidly' maintains 'lthe .coverin locked positionA and 'which can not" be readil-yoperated except with the-use ofsa .specialtoxovlfv or implement. t y Referring .now more particularly .to thedrawing, the frame per secomprises :a cylinder 5.-of lamper deptlr'havingl an .outwardly projecting annular .flange 6= atffits -l'ower-tendyli-his frame is preferably'formedv'of pressed steel.y Upon the 1vinterior 'off this frame andjnear .the -upperend .thereofthere-is` arrangedV anannular shoulder 'l alsoyformedofsteel. This `:shoulder may* be v.formed yintegral with v thedrame vli'i-v desired, but lis .preferably-a steel '-f-ring-:of ja diameter-l to snugly fitgvwithin'thejframeand is weldedthereto.' The upper@ ,edge of theA shoulder f will :be:v :disposed a distance belowthe upper`edge-o ,the:trarne corresponding to the thickness of the cover plate 8. The upper face of the shoulder 7 and that 30` portion of the cover 8 which engages the same f will be machined so as to insure a proper seating of the cover upon the shoulder throughout the circumference of the plate. It will beunderstood, of course, that the upper face of the cover plate may be provided with-grooves, projections or recesses to promote traction to the wheels o vehicular traflic passing thereover.

The locking means for the rcover includes a pair of spaced parallel stirrups Aor lugs 9 depending from the lower surface of the plate 8. These lugs are apertured as atl() to slidably receive a lock bolt 1l. This lock4 bolt is preferably rectangular in cross section while the openings 10 are similarly formed to prevent rotation of the `l5 bolt within the stirrups. The innermost lug has its opening elongated vertically to permit a limited degree of play or movement of the bolt therein. The rear end of the bolt is provided with a -hook portion 12 disposed rbeneath an v50 aperture 1 3 near the central portion ofthe cover plate 8, the said hook portion affording means whereby the bolt may be retracted or projected by the insertion of a tool or instrument 14 through the said. aperture. The lower end of this adjacent portion of the lug 9. r

the said instrument to be engaged beneath the hook 12 in order that the said bolt may be lifted withinthe lug recess.

' 'Ihe underface of the bolt 11 is notched or recessed at 16 at such point that the recess will receive the adjacent portion of the innermost stirrup orv lugvwhen thebolt isy in projected or lockingposition.` If desiredjastopA 17 may be secured to the underface of the bolt to engage wtih the said lug and to limit the project; ing movement of the said bolt.

be lifted so that the recess 1`6wi11 Interposed between theunderface of tliecovezr 8 and the bolt 11 is an"exp`ansion"'spring"18.

The upper end of this springis engagedoverjastud,19 secured to the cover .while its lower "end -encloses the" upper4 endof` a cotter `pin or. key extending upwardly through a Asuitable 'openingin Lthebolt '11. The spring ist so posi- (tion'edf relative to lthelfbolt 11` that it becomes -cockedfin opposite 'directions as the bolt-is projected or-retracted. In other Words,-=when the .bolt is projected, thespring exertsapressure `tendingto force the bolt into such position at y the same time it forces the said bolt down firmly in vcontact with thel retaining stirrups or' lugs.

`In retracting the'bolt it is `necessary that the 'samefbe-liftedagainst the tension of the* spring 18- until the recess-16 clears the Vadj'acent'icilor-V `tion `of the lug, whereupon'retractin of the bolt f causes the spring 18- to cock in such" position las to tend to hold-the bolt in retracted position.`

This withdrawing movement ofthe bolt kis lim- 'ited'by the `protruding endfof thecotter pinf`20 aswell asthe lower end of the 'spring-itself. 'j

All partsfjof the frame and rcover arevorf t forgedsteel",l vanltftlie stirrups or lugsg 9 `are Weldedto the under'face of the saido'ver."4 latter is `provided with a` "hook 2li-at aV point diametrically opposite tok the bolt 11'to 'engage beneath the shoulderj'ZQ-It will be lunderstood that injapplying the cover lto` the frame, the

f same is tilted'in 'suchV position thatwth'efhook 21" will`f engage` beneath' Athe shoulder '7g -wwith o 1t is Qbviolls, therefore, that in order to retract the bolt -tV is necessary that the inner or rearend; thereto/fgl clear; .the f* pable of. overcoming' the objections set forth as the bolt 11 retracted they cover will belowered, this action causing the hooi:k 21 to engage beneath the shoulder. When properly in place, the tool14 is insertedthrough the opening 13 and the hook end 12 of the bolt is engaged I thereby and moved outwardly, whereupon the recess 16 receives the adjacent portion ofthe lug :9.- and thegvbolt `isrfthus:` held` locked or projected position'.,.v.f, Thereverse4 of `theaej'foperay tions is performed in removing the cover, and

well as `obtainingthe objects outlined, and while "the" presenti's"a disclosure of the invention in Vits.:pre1erred embodiment, it is nevertheless to be understood that variations in the, detailsA of construction; Yassemblage 'and arrangement of parts` maybey resorted to `if i desired without deL parting" fromy the v'spirit i of the inventionVT4 'as In a manhole `rconstruc'tion;-a frame'vprovidedr witha' shoulde'r`,`aremovable 1` cover 4for said frame, bolt Vsupporting means'dependi-ng from the cover-,11a bolt slidably vmounted* in said' sup'- fshould it be required, ythe tool 14 may be en-I porting means `and so positioned as to cooper.'-

ate With'said -shuldenisaid bolt 'having a-notch len'gageab1'e`withY a Vcomplemented flxedportion' of said supporting meansyfand aspring inter- Dosedbetween the'cover anduthe boltand normallyac'ting to Vapply downwardv pressure upon *the* bolt','-fsaid spring being `sov connectedwith -the bolt ytts-'to -be 'co'ckedto different` positions byflroc'llzinfg and unlockingvmover'nent of the bolt, Vsaidspring being-soconstructed and arranged asto also apply-'yieldabletensionwto the' bolt in either rectilinear direction`V of =said bolt iniac `cordanc'e-with the -diierent cocked positions, said bolthavingrneans so arranged 'that itmay be engaged and operated by a toolinsertedthrough f larriopeninlginthecover.` j

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